Isolated discrete upper septal thickening in a non-referral cat population of senior and young cats

Introduction/objectives

Discrete upper septal thickening (DUST) is a phenotype of elderly people. The cardiac phenotype in senior cats has been incompletely described. We aimed to characterize the echocardiographic phenotype of senior cats, specifically to determine prevalence of DUST and hypertrophic cardiomyopathy (HCM).

Animals

One hundred and forty-nine healthy, normotensive cats.

Materials and methods

Prospective cross-sectional study. Senior (≥nine years) and young (<six years) cats were recruited from non-referral population. We defined DUST as an isolated basilar septal bulge, and HCM as left ventricular wall thickness ≥6 mm. An interventricular septum ratio (basal-to-mid septal thickness ratio) was calculated. We assessed for associations between clinical and echocardiographic variables and DUST. Data are presented as mean (±SD), median (range), or frequency (percentage).

Results

One-hundred and two senior and 47 young cats were enrolled. Aortoseptal angle (AoSA) was steeper in senior cats (137° (±14.5) vs. 145° (±12.3) in young cats, p=0.002). Eighteen cats had DUST (18/149, 12%), fourteen senior, and four young cats (p=0.4). Cats with DUST had steeper AoSA (125° (±8.3) vs. 142° (±13.7), p<0.0001) and higher interventricular septum ratio (1.4 (1.2–2.0) vs. 1.0 (0.7–1.8)). Univariable analysis showed decreased odds of DUST with greater AoSA (OR 0.9, p<0.0001), age was not associated with DUST. Twenty-nine senior cats had HCM (28.4%).

Discussion/conclusions

Prevalence of DUST was 12%. There was no association between age and DUST. Smaller/steeper AoSA was the main factor associated with DUST. There was a high prevalence of HCM in this senior population.